is it worth it. fast90 to a new 92
Nope, but the one that got what you're looking for has been posted already! 
Couldn't of said it better myself.
Skull, save your money and give it to a good head porting company like AI, TEA, Livernois or PRC.
I thought the only difference between the 90 and 92 was the slightly bigger opening (by 2 mm) and the fact the internals are openable the same as the 102. If that's the case, then you prolly won't see any performance gain at all, 2mm bigger opening is meaningless...and nothing that you can't open up yourself on the 90.
Skull, save your money and give it to a good head porting company like AI, TEA, Livernois or PRC.
